1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to allotting resources for a wireless network device and, more particularly, to allotting resources for a wireless network the same that actively reacts to a packet transmission rate, thereby maintaining quality of service (QoS) and using network resources efficiently.
2. Description of the Related Art
Development of high-quality multimedia devices such as set-top boxes, digital televisions, personal digital assistants (PDAs), and wireless Internet devices brings various architectures which increases a user's demand for a multimedia service. Accordingly, network designers and engineers have endeavored to design a system that can meet the increased demand for real-time and non real-time multimedia data transmissions.
The Internet Protocol (IP) provides a “best effort service”, which does not secure a service level for a user. The best effort service via an IP network is able to simplify a network because a complexity of a network exists in an end-host. The remarkable growth of Internet shows how effective the best effort service is.
The IEEE 802.11 wireless LAN (WLAN) standard is a popular technology of broadband wireless access for mobile devices. IEEE 802.11 can be considered as a wireless version of “Ethernet” because IEEE 802.11 supports the best effort service. The IEEE 802.11 working group provides a new supplement to the conventional legacy IEEE 802.11 medium access control (MAC) layer in order to support quality of service (QoS).
The new IEEE 802.11e MAC standard provides applications such as sound and video services via the WLAN, so that the application of IEEE 802.11 is extended. The IEEE 802.11e standard is a general wireless standard for industries that support QoS. The IEEE 802.11e continuously interacts with home, business, and public access networks, which still provides a feature for meeting each type of network's own demand. The IEEE 802.11e is perfectly compatible with the conventional legacy standard, and provides wireless standard via home and business environments by adding a QoS feature and business environments to the conventional IEEE 802.11 standard.
QoS support for multimedia data is important to a home network where voice, audio, and video data is transmitted to several networked home electronic devices and personal computers. A broadband service provider considers that the QoS and multimedia network are essential to provide a user with a value-added service such as ready-made video, voice via ready-made video IP, and high-speed Internet access.
To provide an appropriate service, it is necessary for a network service to have a certain quality level, and for a network to be able to separate traffic having a strict timing requirement to avoid delays, jitters, and losses from a different type of traffic. Also, a QoS protocol is required. The QoS does not generate bandwidth, but efficiently manages bandwidth in order to meet a wide range of demands. The QoS is to provide best effort services and several levels of prediction over the current Internet protocol.
The IEEE 802.11e standard discloses a protocol for negotiating a QoS requirement for a traffic stream. A scheduler in a hybrid coordinator decides a service schedule for each station. Scheduling is performed to meet the pre-negotiated QoS requirement.
A station requests the allotting of resources to an access point for transmitting packets, and the access point allots the resources requested by the station, which may be efficient to secure QoS, but may reduce the efficiency of use of the limited resources. Resources, which are requested from the access point by the station in order to transmit packets, do not consider a transmission rate of a physical layer. Accordingly, it is difficult to efficiently use the limited resources if the transmission rate of a physical layer is high or low for resources requested by the station.
FIG. 1 depicts a method of allotting resources between a general station and an access point.
In the method of allotting resources between a general station and an access point illustrated in FIG. 1, a station 10 calculates resources needed to transmit packets to an access point 20 (S10), and requests resources based on the calculated result from the access point 20 (S20). Then the access point 20 determines whether there are resources that can be allotted to the station 10 (S30).
If the access point 20 can allot the resources requested by station 10, the access point 20 allots the resources to the station 10 (S40).
In the method of allotting resources between a general station and an access point, the station does not consider a transmission rate of a physical layer where packets are transmitted. When the resources allotted to station are less than the transmission rate of the physical layer, the time allotted for transmitting packets is increased. When the resources allotted to a station are more than the transmission rate of the physical layer, surplus resources exist. Accordingly, it is necessary for the QoS to be efficiently secured by managing resources according to the transmission rate of the physical layer.
The Korean Unexamined Patent No. 10-2005-0057124 discloses a method of providing a QoS service schedule that creates a QoS schedule for a wireless station in a wireless network, and transmits the created QoS schedule from a hybrid coordinator to the wireless station, which is capable of using the QoS schedule in the wireless station to perform power management by entering a power save mode during times when the hybrid coordinator has not scheduled any transmission opportunities; however, a method of using WLAN resources efficiently by actively reacting to a changing transmission rate of a physical later and maintaining QoS is not disclosed.